Page:Harvesting ants and trap-door spiders. Notes and observations on their habits and dwellings (IA harvestingantstr00mogg).pdf/192

 made excursions to catch the flies with which I supplied her, but remained self-immured in her cell.

It would be interesting to discover whether any of the spiders of this group (but which do not construct trap-door nests) pass the winter in similar structures.

H.

On the Structure of Cork Doors.

In order to test my theory to the effect that the trap-door nests are enlarged from time to time, and that the numbers of layers of silk in an undisturbed cork door should represent the number of enlargements which the nest has undergone, I examined the doors of twenty-eight nests of the cork type (all I believe of N. cæmentaria), in order to prove whether as a rule the larger cork doors do contain more layers of silk than the small ones, as they should on this hypothesis. This is, I think, fairly established by the following table:—  Comparative Table.

One cork door measuring 1    line across contained 1 layer of silk. Four "  doors  "       1-1/2 lines   "             3 layers One   "  door   "       1-1/2         "             2       " One   "  door   "       1-3/4         "             4       " One   "  door   "       2             "             5       " Two   "  doors  "       2-1/2         "             6       " One   "  door   "       2-1/2         "             5       " One   "  door   "       3             "             8       " Two   "  doors  "       3-1/2         "             5       " One   "  door   "       3-1/2         "             7       " One   "  door   "       4             "             7       " Two   "  doors  "       4-1/2         "             8       " One   "  door   "       4-1/2         "             7       " Two   "  doors  "       5             "             9       " One   "  door   "       5             "             5       " One   "  door   "       5             "             6       " One  "  door   "       5             "            13       " One  "  door   "       5-1/2         "             9       " One  "  door   "       5-1/2         "            10       " One  "  door   "       5-1/2         "            14       " One  "  door   "       6             "            12       "